The splitting of atoms, also known as nuclear fission, produces radiation and radioactivity. Dr Lise Meitner discovered how radioactivity could be produced in 1939. She found that firing a small particle called a neutron into another atom could cause radiation to be released. Radioactive atoms created in this way can be useful for detecting cancer or checking whether the body’s organs are working properly. When radioactive atoms are injected into the blood of a patient, they travel through the body and release radiation that can be detected using special cameras, creating images or videos of the body’s tissues. In this way, radiation helps doctors to better diagnose and treat patients. Unfortunately, Dr Meitner faced many obstacles and was never credited officially for her key discovery of nuclear fission.